Last April I tested Deep Blue’s unique and effective Anchor Alert (now $795), which measures actual movement at the hook and uses sonar pings to report back to a small display on the boat. A new version will add a BlueBox wireless transmitter able to talk to the company’s $389 BlueNet Mobile Display anywhere onboard and—with the addition of an upcoming high-gain repeater—up to two miles away from the boat. Already available for BlueNet wireless are a $329 chain counter and a $469 SDT (speed, depth, and temperature) transducer. On the planning board are a man overboard alarm and tracking system that transmits under water instead of on top of it (problematic when rough), a diver traffic control system, and a 6.5-inch mobile touchscreen color display.